Mr Brown said he had set up Operation Sweep to target crime hotspots over the next three months.

He said crime rates traditionally fell over winter before steadily increasing into the summer months and the spike was disturbing.

"We don't know why this is happening, at this point in time," he said.

"But we're acting now by pushing our focus with greater resources and greater effort and energy into this space to do something immediately, rather than to wait until we fully understand what's occurring here."

He said the figures showed there had been a 34 per cent spike in domestic assaults in the past 12 months — from 734 in 2014-15 to 983 in 2015-16.

That could be attributed to a number of problems in the community, he said.

"Alcohol, methylamphetamine, tensions within households, more people living within smaller spaces and the impact of fly-in, fly-out mining, because that is what, anecdotally, my police officers report to me," he said.

"A change in the construct of family life generally, but it's really hard to know."

Mr Brown said the figures also showed police prosecutions were up 11 per cent and the arrest of repeat offenders had increased 41 per cent.